1. Field of the Invention
The present invention relates to a motor provided with a chucking device, and, more particularly, to an arrangement and structure of an attracting magnet for suppressing vibrations of a rotating body of the motor. Further, the present invention also relates to a disk driving device equipped with the motor.
2. Description of the Related Art
In recent years, as a disk driving device for optically recording and reproducing an optical disk (hereinafter simply referred to as a “disk”), such as a DVD, a CD, or the like, becomes thinner, there are increasing demands for a low-profile motor mounted to the disk driving device for rotating the disk. This kind of motor includes a chucking device for removably holding the disk, the chucking device having a mounting portion to which the disk is mounted.
Recently, the recording pitch of the disk has grown to be narrower as the storage capacity thereof increases. For that reason, the light used in recording and reproducing the disk needs to be irradiated with increased accuracy. Moreover, the motor needs to be rotated at a high speed as the requirements of recording and reproducing the disk become faster.
It becomes difficult to reduce surface vibration of the disk because the low-profile design of the motor results in a decrease in the length of a bearing part that rotatably supports the rotating body of the motor. When the disk is rapidly rotated by the motor, a problem is posed in that the disk may be off-centered due to an unbalance with respect to the rotational center thereof. This problem becomes apparent if the disk is rotated at a high speed.
As a solution to the problem noted above, there has been proposed a structure in which an attracting magnet for magnetically attracting a rotating body of a motor is arranged to oppose the rotating body, thereby suppressing floating and vibration of the rotating body.
However, the space required for installing the attracting magnet within the motor gets smaller when the motor is designed to provide a low-profile shape. In addition, if the attracting magnet is arranged in contact with a stator that forms a magnetic circuit for generating a motor driving force, the magnetic circuit may be influenced by the stator, which may negatively affect the motor efficiency.